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International audienceTensile tests and simple shear tests have been performed on Armco iron sheets before hydrogen cathodic charging, in order to study the effect of loading mode on blistering of plastically prestrained samples. The experimental results from surfometry and image analysis show the decrease of the blisters size with prestrain increase, and quantitative differences between tensile or shear prestrain are exhibited. Phenomenological modeling of blister initiation is proposed, based on void expansion increase under internal pressure, and considering both plastic strain and pores as traps during hydrogen transport. Finite element simulations of material expansion due to hydrogen induced void growth lead to qualitative agreement with experimental tendencies

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In this paper, we present techniques for fatigue damage evaluation using spectral methods and a model taking into account elasto-plastic behaviour. The model is associated with a non linear fatigue law, covering the whole endurance domain (low cycle and high cycle fatigue). It uses Neuber’s method and is valid for limited plasticity. To validate this modeling, we perform a correlation between spectral methods, modified spectral methods and experimental data. We present here, the results obtained in the case of narrowband random vibrations.

In this paper, we present techniques for fatigue damage evaluation using spectral methods and a model taking into account confined elasto-plastic behavior. The model is associated with a local fatigue approach, covering the whole endurance domain (low cycle and high cycle fatigue). It uses Neuber's method and is valid for limited plasticity. To validate this modeling, we perform a correlation between spectral methods, modified spectral methods and experimental tests. Results presented here are focused on the uniaxial loading case.